My new (old) bus has a Webasto System but I am having problems understanding how it works? There is a thermostat in the kitchen area that has an Off/On switch at the bottom and a lever at the top to set the temperature, just like you would have on the wall at your house.

When I turn the switch to On the Webasto runs for a little while and then fires up. It will continue to run for several minutes prior to shutting down. During this time I can feel hot water at each of the water coils inside the coach but I can't see a way to get the fans to run? I assume that there is a switch that senses the water temperature at a given temperature and then turns the fan on?

Each of the coils have a toggle switch mounted next to them in the wall but I've tried moving these with no success. I have looked to see if I can find a relay or some form of switch that would control the fans but not sure what I am looking for and I don't find anything.

The odd thing is that there is another thermostat in the back of the coach that has wires running to it but it doesn't seem to do anything? I have no schematics or any information on how this system works?

The AquaStats control the fan motors on most applications I don't know how yours is hooked up they are all different can you check the temperature of the water it may not be hot enough or the pump is not circulating the water

Is the Webasto shutting off properly, going through the cool down cycle? Fire goes out and it runs for about 4 mins. It sounds like circulation pump might not be circulating. Fire it up and put your hand on the pump and see.

After sitting that long Doug it is likely there is air in the system. Without coolant circulation the burner will overheat and it will automatically shut down. As we discussed, the expansion tank should be the highest point in the system and should be around 2/3 full, they need to be topped off once in a while. You may have to bleed the toe kicks to get the air out also. Most of the toe kicks have two speed fan switches. You are going to have to get behind your toe kick heaters with a IR gun and see if the lines are getting warm but it sure sounds like the coolant is not circulating to me. Are all the valves open?